Refrigerator dismantling method, compression equipment, and refrigerator dismantling device

ABSTRACT

A refrigerant gas is collected and a compressor is removed from a discarded refrigerator, a heat-insulating housing including a heat insulator is cut/processed and separated into a plurality of pieces, and the pieces are compressed/processed by compression rollers opposing each other so as to collect a gas contained in the heat insulator. In accordance with this method, substantially no gas contained in the heat insulator is diffused at the time of cutting the heat-insulating housing, and the gas can be collected at a high concentration because it is collected by being allowed to leak out at the time of compressing. Furthermore, by using the compression rollers, closed-cells in the heat insulator can be crushed easily, thereby collecting the gas completely and reliably. Thus, it is possible to collect a foaming gas contained in the heat insulator efficiently and disassemble a refrigerator at low cost without increasing the size of equipment and an installation space.

TECHNICAL FIELD

The present invention relates to a method and a device for disassemblinga discarded refrigerator. Also, the present invention relates to acompressing device that can be used suitably for disassembling arefrigerator.

BACKGROUND ART

Generally, a heat-insulating housing of a refrigerator is formed of alayered body including a steel (including iron and cast iron) plate asan outer wall material, a resin plate as an inner wall material and aheat insulator interposed between the steel plate and the resin plate.The heat insulator is made of urethane foam or the like, andchlorofluorocarbons are used as a foaming agent therefor. Sincechlorofluorocarbons may destroy an ozone layer, it is necessary tocollect them at the time of disposing of a refrigerator and prevent themfrom diffusing into the air. It also is desired that the steel plate andthe resin plate should be collected for recycling.

As a conventional method for disassembling a discarded refrigerator, amethod described in JP 2679562 B is known, for example. The following isa brief description of this method.

After a steel plate and a resin plate are removed from a heat-insulatinghousing, urethane foam first is cut into pieces of approximately 5 cmsquare, which are put into a hopper and sent to a crusher. In theprocess where external mechanical force is applied in the crusher so asto crush the urethane foam, closed-cells therein are destroyed.Chlorofluorocarbons released from the closed-cells and the crushedurethane grains are sent to a bag filter together with the air, so thata gaseous component and the urethane grains are separated. The gaseouscomponent is cooled down in a condenser, so that the chlorofluorocarbonsare liquefied and separated, and then the gas that is not condensed issent back to the hopper. In this manner, the chlorofluorocarbonscontained in the urethane foam can be separated and collected withoutbeing diffused into the air.

However, in the above-described disassembling method, after crushing theurethane foam, in order to separate the urethane grains and the releasedchlorofluorocarbons, a mixture thereof is sent with the air to the bagfilter, so that they are separated by utilizing a wind power. Thus,since the chlorofluorocarbons are diffused in the carrier air, theconcentration of the chlorofluorocarbons becomes extremely low. Undersuch conditions, the condensation and separation of thechlorofluorocarbons is by no means efficient. Furthermore, the equipmentfor carrying out these processes is large, raising equipment costsconsiderably.

Moreover, both the crusher for crushing the urethane foam and theseparator for separating the urethane grains and the gaseous componentgenerally are very large, which require a large installation space andcost much.

DISCLOSURE OF INVENTION

It is an object of the present invention to solve the conventionalproblems described above and to provide a disassembling method and adisassembling device that can collect a foaming gas efficiently anddisassemble a refrigerator at low cost without increasing the size ofequipment and an installation space. It also is an object of the presentinvention to provide a compressing device that can be used suitably forthe above method for disassembling a refrigerator.

In order to achieve the above-mentioned objects, the present inventionhas the following configurations.

A method for disassembling a refrigerator of the present inventionincludes the processes of collecting a refrigerant gas and removing acompressor, cutting/processing and separating a heat-insulating housingincluding a heat insulator into a plurality of pieces, andcompressing/processing the pieces by compression rollers opposing eachother so as to collect a gas contained in the heat insulator.

With the above configuration, first, a refrigerant gas (for example,chlorofluorocarbons) is collected and a compressor is removed.Therefore, the refrigerant gas can be collected reliably, and it ispossible to prevent the refrigerant gas from diffusing into the air inthe later process. Next, since the heat-insulating housing is cut andseparated into a predetermined shape and size, the gas contained in theheat insulator seldom is diffused in this process, and it is easy tohandle each of the cut pieces thereafter. Also, since theheat-insulating housing may be cut without removing a steel plate and aresin plate that sandwich the heat insulator, the process can besimplified. Finally, the pieces that have been cut and separated arecompressed and the gas in the heat insulator is made to leak out andcollected, so that it is easy to collect the gas at a highconcentration. In addition, since the pieces are compressed by thecompression rollers, closed-cells in the heat insulator can be crushedeasily, thereby collecting the gas contained therein completely andreliably. Furthermore, a foaming gas does not remain in the compressedpieces, which thus can be recycled directly. Moreover, the device forcarrying out the above method can be miniaturized with an extremelysimple configuration and does not require a large installation space.Therefore, the disassembling of a refrigerator and a recycling systemthereof can be provided at a low cost.

In the above disassembling method, it is preferable that theheat-insulating housing is cut/processed to be at least one ofsubstantially flat, substantially U-shaped and substantially L-shapedpieces. As described above, in the disassembling method of the presentinvention, it is sufficient to cut and separate the heat-insulatinghousing into the size and shape allowing the latercompressing/processing. Even the heat-insulating housing having othermembers layered thereon may be cut without separating these members.

For example, the process of cutting/processing and separating theheat-insulating housing may include a process of cutting/processing theheat-insulating housing so as to remove a door and a process of slicingthe heat-insulating housing into cross sections, each of predeterminedthickness. Alternatively, the process of cutting/processing andseparating the heat-insulating housing may include a process ofcutting/processing the heat-insulating housing so as to remove a doorand a process of cutting/processing and separating the heat-insulatinghousing into a plurality of substantially flat pieces and at least onesubstantially L-shaped piece. Alternatively, the process ofcutting/processing and separating the heat-insulating housing mayinclude a process of cutting/processing and separating theheat-insulating housing into pieces of a door, a top plate, a bottomplate, a side plate, a back plate and a partition plate.

The cutting and separating process in the above disassembling methodalso can be performed in the following method.

In a first cutting and separating method, by using a cutting deviceincluding a rotor with a principal plane, a spindle provided in a normaldirection to the principal plane, and at least one impacting bodymounted on the spindle rotatably, wherein the impacting body is mountedso that a predetermined fitting gap is provided between the impactingbody and the spindle and a part of a periphery of the impacting body canbe positioned beyond a periphery of the rotor, the heat-insulatinghousing is cut/processed by rotating the rotor at a high speed to allowthe impacting body to impact on the heat-insulating housing at least ata critical impact velocity. The “critical impact velocity” refers to anintrinsic physical property value to a material of a heat-insulatinghousing to be cut and processed and, when the heat-insulating housing isa composite material of a plurality of materials with different criticalimpact velocities, means the largest critical impact velocity amongthem. In accordance with this first cutting and separating method, evenwhen the heat-insulating housing has a structure in which differentmaterials are intermixed or each heat-insulating housing has a differentstructure, the heat-insulating housing can be smashed or cut at a highspeed with a common cutting device without taking such a structure intoconsideration. In addition, an impact cutting utilizing a centrifugalforce can reduce abrasion of the impacting body serving as a cuttingblade, thereby extending a lifetime of the cutting device and improvingits reliability.

In the above first cutting and separating method, it is preferable thatthe impacting body is allowed to impact on the heat-insulating housingat a speed of at least about 139 m/second (about 500 km/hour), and it ismore preferable that the impacting body is allowed to impact at a speedof at least about 340 m/second (about 1224 km/hour). It also ispreferable that the impacting body is allowed to impact on theheat-insulating housing at a frequency of at least about 150 times/min.This allows a high-speed cutting regardless of a material and a kind ofthe heat-insulating housing.

Also, in the above first cutting and separating method, it is preferablethat the impacting body is allowed to impact on the heat-insulatinghousing at a speed at least twice as high as the critical impactvelocity of the heat-insulating housing. This allows a high-speedcutting regardless of a material and a kind of the heat-insulatinghousing.

Furthermore, in the above first cutting and separating method, it ispreferable that the impacting body cuts the heat-insulating housing byimpacting on the heat-insulating housing to smash a surface thereof.This allows a high-speed cutting regardless of a material and a kind ofthe heat-insulating housing.

In a second cutting and separating method for performing the cutting andseparating process in the disassembling method of the present invention,by using a cutting device including at least a first rotating unit and asecond rotating unit, each of these rotating units including a rotorwith a principal plane, a spindle provided in a normal direction to theprincipal plane, and at least one impacting body mounted on the spindlerotatably, wherein the impacting body is mounted so that a predeterminedfitting gap is provided between the impacting body and the spindle and apart of a periphery of the impacting body can be positioned beyond aperiphery of the rotor, the impacting body of the first rotating unitand the impacting body of the second rotating unit are allowed to impacton the heat-insulating housing sequentially while rotating the rotatingunits in a plane parallel with the principal plane of the rotor at ahigh speed and holding the first and second rotating units so that acircular path of a tip of the impacting body of the first rotating unitand a circular path of a tip of the impacting body of the secondrotating unit during the rotation substantially are on the same plane, acutting depth by the impacting body of the second rotating unit is madelarger than that by the impacting body of the first rotating unit, andthe impacting body of at least one of the rotating units is allowed toimpact on the heat-insulating housing at least at a critical impactvelocity, whereby the heat-insulating housing is cut/processed in adirection substantially parallel with the principal plane of the rotor.The “critical impact velocity” refers to an intrinsic physical propertyvalue to a material of a heat-insulating housing to be cut and processedand, when the heat-insulating housing is a composite material of aplurality of materials with different critical impact velocities, meansthe largest critical impact velocity among them. In accordance with thissecond cutting and separating method, while rotating at least tworotating units, the impacting bodies thereof are allowed to impact onthe heat-insulating housing by sequentially increasing the cuttingdepths by the impacting bodies. At this time, the impacting body of atleast one of the rotating units is allowed to impact at least at thecritical impact velocity of the heat-insulating housing. Accordingly,even when the heat-insulating housing has a structure in which differentmaterials are intermixed or each heat-insulating housing has a differentstructure, the heat-insulating housing can be smashed or cut at a highspeed with a common cutting device without taking such a structure intoconsideration. In addition, an impact cutting utilizing a centrifugalforce can reduce abrasion of the impacting body serving as a cuttingblade, thereby extending a lifetime of the cutting device and improvingits reliability. Moreover, by allowing the impacting body to impact onthe heat-insulating housing such that the cutting depths of a pluralityof the rotating units increase sequentially, a stable and excellentcutting performance can be achieved even when the heat-insulatinghousing is thick or a plurality of members with different physicalproperties are layered in a thickness direction.

In the above second cutting and separating method, the impacting body ofthe first rotating unit, which impacts on the heat-insulating housingfirst, can be allowed to impact on the heat-insulating housing at leastat the critical impact velocity. When a top layer of the heat-insulatinghousing is formed of a hard material (a difficult-to-machine material)such as metal and a relatively soft material such as resin is layered onits back side, for example, only the difficult-to-machine material layeras the top layer is cut by the first rotating unit, and the soft layerbelow is then cut by the second rotating unit. At this time, by allowingthe impacting body of the first rotating unit to impact at least at thecritical impact velocity of the difficult-to-machine material layer asthe top layer, the difficult-to-machine material layer can be cut by aprocessing principle that will be described later. In this manner, inthe case where the heat-insulating housing is formed by layeringdifferent kinds of materials, the rotational speed of each rotating unitis set according to physical properties (the critical impact velocity)of each layer, thereby allowing the impacting body to impact on each ofthese layers, so that an efficient and stable cutting can be achieved.In the above example, it is preferable that the impacting body of thesecond rotating unit, which cuts the soft layer below, also is allowedto impact at least at the critical impact velocity of this soft layer,but there are some cases where, depending on the material of the softlayer, the soft layer can be cut excellently even when allowing theimpacting body to impact at the critical impact velocity or lower.

Also, in the above second cutting and separating method, the rotatingunits can be provided on a common base. This makes it possible toconfigure a compact cutting device. Also, it becomes easier to controlthe position of each rotating unit.

Furthermore, in the above second cutting and separating method, theimpacting body can have a different shape in each of the rotating units.For example, an optimal shape of the impacting body is selectedaccording to a rotational speed of the rotating unit, a radius ofgyration of the impacting body or a cutting depth thereof, therebybalancing a cutting performance, cost and an installation safety in anexcellent manner.

Moreover, in the above second cutting and separating method, it ispreferable that the impacting body of at least one of the rotating unitsis allowed to impact on the heat-insulating housing at a speed of atleast about 139 m/second (about 500 km/hour), and it is particularlypreferable that the impacting body of at least one of the rotating unitsis allowed to impact at a speed of at least about 340 m/second (about1224 km/hour). It also is preferable that the impacting body is allowedto impact on the heat-insulating housing at a frequency of at leastabout 150 times/min. This allows a high-speed cutting regardless of amaterial and a kind of the heat-insulating housing.

In the above second cutting and separating method, it is preferable thatthe impacting body of at least one of the rotating units is allowed toimpact on the heat-insulating housing at a speed at least twice as highas the critical impact velocity of the heat-insulating housing. Thisallows a high-speed cutting regardless of a material and a kind of theheat-insulating housing.

Also, in the above second cutting and separating method, it ispreferable that the impacting body that impacts on the heat-insulatinghousing at least at the critical impact velocity cuts theheat-insulating housing by impacting on the heat-insulating housing tosmash a surface thereof. This allows a high-speed cutting regardless ofa material and a kind of the heat-insulating housing.

Furthermore, in the above second cutting and separating method, it ispreferable that, when the heat-insulating housing is formed by layeringat least a first layer and a second layer that have different criticalimpact velocities, the first layer is cut mainly by the impacting bodyof the first rotating unit, the second layer is cut mainly by theimpacting body of the second rotating unit, and an impact velocity ofthe impacting body of the first rotating unit against theheat-insulating housing is made different from that of the impactingbody of the second rotating unit against the heat-insulating housing. Inother words, when the heat-insulating housing is formed by layering aplurality of layers with different critical impact velocities, thecutting depths of the impacting bodies of the rotating units areadjusted, thus cutting different layers with different rotating units.This makes it possible to set optimally the impact velocities of theimpacting bodies of the rotating units according to the respectivecritical impact velocity of the layer they cut. As a result, anefficient cutting becomes possible. In addition, an unnecessaryhigh-speed rotation of the rotating unit can be avoided, and anexcessive installation design and a wasteful energy consumption can besuppressed.

Moreover, in the above second cutting and separating method, it ispreferable that, when the heat-insulating housing is formed by layeringat least a first layer and a second layer that has a critical impactvelocity smaller than the first layer, the first layer is cut mainly bythe impacting body of the first rotating unit, and the second layer iscut mainly by the impacting body of the second rotating unit. In otherwords, when the heat-insulating housing is formed by layering layerswith different critical impact velocities, the first layer with a largercritical impact velocity is cut first using the first rotating unit, andthen the second layer with a smaller critical impact velocity is cutusing the second rotating unit. In general, it is preferable to increasethe impact velocity of the impacting body as a material to be cut has alarger critical impact velocity. However, in order to increase theimpact velocity of the impacting body, the rotating unit has to berotated at a high speed, which generates a larger centrifugal force.This brings about the need for a weight reduction for suppressing thegeneration of centrifugal force or the need for a reinforcement of theimpacting body. On the other hand, a smaller cutting depth allows aminiaturization of the impacting body, making it possible to reduceweight, which can suppress the generation of the centrifugal force.Thus, by cutting the first layer with a larger critical impact velocityfirst, it becomes possible both to secure the necessary impact velocityof the impacting body and to reduce the centrifugal force that isgenerated.

In this case, it is preferable that the cutting depth by the impactingbody of the first rotating unit is equal to or larger than a thicknessof the first layer. This allows the first layer with a larger criticalimpact velocity to be cut by the first rotating unit. Therefore, itbecomes unnecessary to cut the first layer with the second rotatingunit, so that a load on the second rotating unit can be reduced. Forexample, the impact velocity of the impacting body of the secondrotating unit can be set lower than that of the first rotating unit.

It is preferable that the impacting body of the first rotating unit isallowed to impact on the first layer at least at the critical impactvelocity of the first layer, in particular, at a speed at least twice ashigh as the critical impact velocity of the first layer. In this manner,the first layer that is difficult to cut can be cut stably based on aprocessing principle described later. Also, a stable high-speed cuttingbecomes possible along with an increase in the impact velocity of theimpacting body. More specifically, although it depends on a material forthe first layer, the impacting body of the first rotating unit desirablydesirably is allowed to impact on the first layer at a speed of at leastabout 139 m/second (about 500 km/hour), in particular, at a speed of atleast about 340 m/second (about 1224 km/hour). Accordingly, the firstlayer can be cut at a high speed regardless of the material and kind ofthe heat-insulating housing.

On the other hand, the impacting body of the second rotating unit can beallowed to impact on the second layer at a speed not greater than thecritical impact velocity of the first layer. In other words, by cuttingthe first layer almost entirely by the first rotating unit, the impactvelocity of the impacting body of the second rotating unit can be setlower than that of the first rotating unit. This can reduce therotational speed of the second rotating unit, thus relaxing the designstrength of each part of the rotating unit (for example, a spindle, aperipheral region of a through hole of the impacting body through whichthe spindle is passed or the like). This also eliminates the need for alarge driving device for a high-speed rotation. Thus, it becomespossible to reduce cost and improve reliability and safety. In the casedescribed above, it is preferable that the impacting body of the secondrotating unit is allowed to impact at least at the critical impactvelocity of the second layer. In this manner, the second layer can becut stably based on the processing principle of the present inventiondescribed above. Nevertheless, there are some cases where, depending onthe material of the second layer, the second layer can be cut even whenallowing the impacting body of the second rotating unit to impact at thecritical impact velocity of the second layer or lower. In such cases, itis preferable in view of lifetime of the impacting body, cost,reliability, safety and energy consumption that it is allowed to impactat as low a speed as possible.

In the above method, it is preferable that the circular path of the tipof the impacting body of the first rotating unit has a smaller radiusthan the circular path of the tip of the impacting body of the secondrotating unit. By reducing the size of the circular path of the firstrotating unit, it becomes easier to rotate the first rotating unit at ahigh speed. Therefore, the impacting body of the first rotating unit canbe allowed to impact on the first layer with a larger critical impactvelocity at a higher speed.

In the above first and second cutting and separating methods, an outershape of the impacting body can be any one of a polygon with a pluralityof corners, a shape with projections at substantially equal angles onits periphery, a disc shape, a substantially-bell shape, asubstantially-“9” shape and a substantially-bow shape. The shape of theimpacting body is selected according to the impact velocity of theimpacting body, a cutting depth and a material of the heat-insulatinghousing serving as an object to be cut, thereby achieving an efficientcutting device.

Also, in the above first and second cutting and separating methods, itis preferable that the fitting gap between the spindle and the impactingbody is at least 2 mm, in particular, about 5 to 10 mm. When the fittinggap is smaller than the above range, the displacement of the impactingbody caused by the rebound after the impacting body has impacted on theheat-insulating housing cannot be absorbed excellently, lowering acutting performance. On the other hand, when the fitting gap is toolarge, the effect of improving the cutting performance cannot beobtained, or rather the cutting performance deteriorates because theposition of the impacting body is unstable or the adjacent impactingbodies collide with each other.

Next, a compressing device of the present invention includes at least apair of compression rollers opposing each other forcompressing/processing an object to be compressed, a gas diffusionpreventing device for preventing a diffusion of a gas leaking from theobject to be compressed during compressing, and a gas collecting devicefor collecting the gas. With the above configuration, since the objectis compressed by the compression rollers, closed-cells in the object tobe compressed can be crushed easily and reliably, thereby collecting thegas contained therein completely and reliably. Furthermore, a gas ismade to leak out by the compression, and the gas diffusion preventingdevice for preventing a diffusion of the gas further is provided, makingit easier to collect the gas at a high concentration. The gas does notremain in the compressed object after compression, which thus can berecycled directly. Moreover, such a compressing device can beminiaturized with an extremely simple configuration and does not requirea large installation space. Therefore, a gas collecting system can beprovided at a low cost.

Preferably, the above compressing device further includes a carrierdevice for carrying the object to be compressed. With this preferableconfiguration, the compressing process can be automated.

In the above preferable configuration, it is preferable that the carrierdevice is a belt conveyor. With this preferable configuration, theconfiguration of the carrier device can be simplified, thereby achievinga cost reduction.

Also, in the above compressing device, it is preferable that the objectto be compressed is a piece obtained by cutting a heat-insulatinghousing of a refrigerator. With this preferable configuration, thedisassembling of a refrigerator and the recycling system thereof can beachieved with a small space and a low cost.

Next, a first device for disassembling a refrigerator of the presentinvention includes a cutting device for cutting/processing aheat-insulating housing of a refrigerator including a heat insulatorinto a plurality of pieces, and a compressing device forcompressing/processing the pieces with compression rollers opposing eachother so as to collect a gas contained in the heat insulator. Thecutting device includes a rotor with a principal plane, a spindleprovided in a normal direction to the principal plane, and at least oneimpacting body mounted on the spindle rotatably. The impacting body ismounted so that a predetermined fitting gap is provided between theimpacting body and the spindle and a part of a periphery of theimpacting body can be positioned beyond a periphery of the rotor, andthe rotor is rotated at a high speed to allow the impacting body toimpact on the heat-insulating housing at least at a critical impactvelocity.

A second device for disassembling a refrigerator of the presentinvention includes a cutting device for cutting/processing aheat-insulating housing of a refrigerator including a heat insulatorinto a plurality of pieces, and a compressing device forcompressing/processing the pieces with compression rollers opposing eachother so as to collect a gas contained in the heat insulator. Thecutting device includes at least a first rotating unit and a secondrotating unit. Each of these rotating units includes a rotor with aprincipal plane, a spindle provided in a normal direction to theprincipal plane, and at least one impacting body mounted on the spindlerotatably. The impacting body is mounted so that a predetermined fittinggap is provided between the impacting body and the spindle and a part ofa periphery of the impacting body can be positioned beyond a peripheryof the rotor, the impacting body of the first rotating unit and theimpacting body of the second rotating unit impact on the heat-insulatinghousing sequentially while the rotating units are rotated in a planeparallel with the principal plane of the rotor at a high speed and thefirst and second rotating units are held so that a circular path of atip of the impacting body of the first rotating unit and a circular pathof a tip of the impacting body of the second rotating unit during therotation substantially are on the same plane, a cutting depth by theimpacting body of the second rotating unit is larger than that by theimpacting body of the first rotating unit, and the impacting body of atleast one of the rotating units impacts on the heat-insulating housingat least at a critical impact velocity, whereby the heat-insulatinghousing is cut in a direction substantially parallel with the principalplane of the rotor.

In the above first and second devices for disassembling a refrigerator,the “critical impact velocity” refers to an intrinsic physical propertyvalue to a material of a heat-insulating housing to be cut and processedand, when the heat-insulating housing is a composite material of aplurality of materials with different critical impact velocities, meansthe largest critical impact velocity among them.

By using the cutting device of the above first and second devices fordisassembling a refrigerator, even when the heat-insulating housing hasa structure in which different materials are intermixed or eachheat-insulating housing has a different structure, the heat-insulatinghousing can be smashed or cut at a high speed with a common cuttingdevice without taking such a structure into consideration. In addition,an impact cutting utilizing a centrifugal force can reduce abrasion ofthe impacting body serving as a cutting blade, thereby extending alifetime of the cutting device and improving its reliability. Moreover,since only the part subjected to the impact by the impacting body andits vicinity are broken and cut, the gas contained in the heat insulatorseldom diffuses during cutting. Also, it is easy to handle each of thecut pieces thereafter.

Furthermore, in accordance with the cutting device of the second devicefor disassembling a refrigerator, while rotating at least two rotatingunits, the impacting bodies thereof are allowed to impact on theheat-insulating housing by sequentially increasing the cutting depths ofthe impacting bodies. At this time, the impacting body of at least oneof the rotating units is allowed to impact at least at the criticalimpact velocity of the heat-insulating housing. Accordingly, by allowingthe impacting body to impact on the heat-insulating housing such thatthe cutting depths of a plurality of the rotating units increasesequentially, a stable and excellent cutting performance can be achievedeven when the heat-insulating housing is thick or a plurality of memberswith different physical properties are layered in a thickness direction.

According to the compressing device in the first and second devices fordisassembling a refrigerator, the pieces that have been cut andseparated are compressed and the gas in the heat insulator is made toleak out and collected, so that it is easy to collect the gas at a highconcentration. In addition, since the pieces are compressed by thecompression rollers, closed-cells in the heat insulator can be crushedeasily, thereby collecting the gas contained therein completely andreliably. Furthermore, a foaming gas does not remain in the compressedpieces, which thus can be recycled directly.

Moreover, the cutting device and the compressing device described aboveboth can be miniaturized with an extremely simple configuration and donot require a large installation space. Therefore, the disassembling ofa refrigerator and a recycling system thereof can be realized at a lowcost.

In the above first and second devices for disassembling a refrigerator,it is preferable that the compressing device further includes a gasdiffusion preventing device for preventing a diffusion of a gas leakingfrom the pieces during compressing/processing and a gas collectingdevice for collecting the gas. With this preferable configuration, itbecomes still easier to collect the gas at a high concentration.

Also, in the above first and second devices for disassembling arefrigerator, it is preferable that the cutting device is mounted to anarm of a robot with a multi-axis control function. This allows athree-dimensional processing (processing of a curved surface).

In the above first and second devices for disassembling a refrigerator,it is preferable that at least one of an intrinsic oscillatory waveformand an intrinsic oscillation frequency that are caused by an impact ofthe impacting body against the heat-insulating housing, a load on adriving motor for rotating the rotor and an outer shape of theheat-insulating housing is detected, and at least one of a rotationalspeed of the rotor, a cutting depth and a relative speed (a feed speed)and a relative moving direction (a feed direction) between the rotor andthe heat-insulating housing is changed. This makes it possible to setoptimal cutting conditions automatically even when the material of theheat-insulating housing is unknown, allowing an automation of thecutting.

Furthermore, in the above second device for disassembling arefrigerator, it is preferable that at least one of an intrinsicoscillatory waveform and an intrinsic oscillation frequency that arecaused by an impact of the impacting body against the heat-insulatinghousing and a load on a driving motor for rotating the rotor is detectedfor each of the rotating units, and at least one of a rotational speedof the rotor, a cutting depth and a relative speed (a feed speed) and arelative moving direction (a feed direction) between the rotor and theheat-insulating housing is changed for each of the rotating units. Thismakes it possible to set optimal cutting conditions automatically foreach of the rotating units, allowing an efficient cutting.

Preferably, the above first and second devices for disassembling arefrigerator further include a carrier device for carrying each of thepieces that have been cut/processed and separated in the cutting deviceto the compressing device. In this way, the cut pieces can be carriedautomatically or semi-automatically, thus achieving an efficientdisassembling device. This carrier device can be constituted by a beltconveyor and/or a robot arm for grasping and transferring the cut piecesonto the belt conveyor or the compressing device.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic perspective view showing a heat-insulating housingof a two-door refrigerator.

FIG. 2 is a schematic perspective view showing a housing main bodyobtained by removing doors from the heat-insulating housing of thetwo-door refrigerator.

FIG. 3 is a perspective view showing an example of cutting theheat-insulating housing of the refrigerator.

FIG. 4 is a perspective view showing another example of cutting theheat-insulating housing of the refrigerator.

FIG. 5 is a perspective view showing still another example of cuttingthe heat-insulating housing of the refrigerator.

FIG. 6 is a sectional front view (a sectional view taken along the lineVI—VI in FIG. 7) showing a cutting device according to Embodiment B-1 ofthe present invention.

FIG. 7 is a sectional side view, which is taken along the line VII—VIIin the cutting device shown in FIG. 6.

FIG. 8 is a sectional front view showing a state of cutting a workpieceby using the cutting device of Embodiment B-1 of the present invention.

FIG. 9A is a front view showing an impacting body constituting thecutting device of Embodiment B-1 of the present invention, and

FIG. 9B is a sectional view thereof taken along the line 9B—9B in FIG.9A seen in an arrow direction.

FIG. 10 is a top view showing a cutting device according to EmbodimentB-2 of the present invention.

FIG. 11 is a sectional view taken along the line XI—XI in FIG. 10 seenin an arrow direction.

FIG. 12A is a front view showing a specific configuration of a squareimpacting body constituting the cutting device of Embodiment B-2 of thepresent invention, and FIG. 12B is a side view thereof.

FIG. 13A is a front view showing a specific configuration of asubstantially bow-shaped impacting body constituting the cutting deviceof Embodiment B-2 of the present invention, and FIG. 13B is a side viewthereof.

FIG. 14A is a front view showing a modified cruciform impacting body,and FIG. 14B is a side view thereof.

FIG. 15A is a front view showing a disc-shaped impacting body, and FIG.15B is a sectional view thereof taken along the line 15B—15B in FIG. 15Aseen in an arrow direction.

FIG. 16A is a front view showing a regular-hexagonal impacting body, andFIG. 16B is a sectional view thereof taken along the line 16B—16B inFIG. 16A seen in an arrow direction.

FIG. 17A is a front view showing a substantially bell-shaped impactingbody, and FIG. 17B is a side view thereof.

FIG. 18A is a front view showing a modified pentagonal impacting body,and FIG. 18B is a side view thereof.

FIG. 19A is a front view showing a substantially “9”-shaped impactingbody, and FIG. 19B is a sectional view thereof taken along the line19B—9B in FIG. 19A seen in an arrow direction.

FIG. 20A is a front view showing a substantially bow-shaped impactingbody, and FIG. 20B is a side view thereof.

FIG. 21A is a front view showing a substantially bow-shaped impactingbody, and FIG. 21B is a side view thereof.

FIG. 22 is a side view showing a state of cutting a heat-insulatinghousing of a refrigerator by using the cutting device according toEmbodiment B-1 of the present invention.

FIG. 23 is a plan view showing the state of cutting the heat-insulatinghousing of the refrigerator by using the cutting device according toEmbodiment B-1 of the present invention.

FIG. 24 is a front view showing a schematic configuration of acompressing device of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

A method for disassembling a refrigerator of the present inventionincludes the processes of collecting a refrigerant gas and removing acompressor (a refrigerant gas collecting process), cutting/processingand separating a heat-insulating housing including a heat insulator intoa plurality of pieces (a cutting and separating process) andcompressing/processing the pieces by compression rollers opposing eachother so as to collect a gas contained in the heat insulator (acompressing process).

In the following, these processes will be described sequentially.

A. Refrigerant Gas Collecting Process

First, a refrigerant gas (for example, chlorofluorocarbons) in arefrigerator to be disassembled is collected by a known method, and acompressor is removed. This can prevent the refrigerant gas fromdiffusing into the air in the subsequent cutting and separating process.Furthermore, a heat exchanger and an electric controller includingcircuit boards also may be removed at this time. These operations can beconducted manually.

B. Cutting and Separating Process

Next, after attachments such as the compressor are removed, theheat-insulating housing is cut/processed and separated into a pluralityof pieces.

The following is a description of an example of cutting/processing atwo-door refrigerator.

FIG. 1 is a schematic perspective view showing a heat-insulating housingof the two-door refrigerator, which has been subjected to theabove-described refrigerant gas collecting process. A heat-insulatinghousing 1 includes an upper door 2 a, a lower door 2 b and a housingmain body 3.

First, as shown in FIG. 2, the upper door 2 a and the lower door 2 b areremoved by cutting.

Then, the housing main body 3 is cut at various cutting positions andseparated into pieces having a predetermined shape. There is noparticular limitation on the cutting positions as long as pieces havinga size and shape that can be compressed/processed in the subsequentcompressing process can be obtained. In general, it is preferable to cutthe housing main body until substantially flat, substantially U-shapedor substantially L-shaped pieces are obtained. It is more preferable tocut it until substantially flat or substantially L-shaped pieces areobtained, and it is particularly preferable to cut it untilsubstantially flat pieces are obtained. It is not necessary to cut itinto excessively small pieces. When the pieces are too small, not onlydoes its cutting time take longer, but also gases contained in the heatinsulator may leak out during cutting, and handling of the piecesbecomes complicated thereafter.

Specific examples of cutting will be described using FIGS. 3 to 5.

FIG. 3 shows an example in which the housing main body 3 is sliced intocross sections. As shown in this figure, the housing main body 3 is cutby each predetermined thickness along a plane perpendicular to itslongitudinal direction (the vertical direction in FIG. 3) and separatedinto substantially flat pieces of a top plate 4 a, a bottom plate 4 b,partition plates 4 c and 4 d and substantially “U”-shaped pieces 5 a, 5b, 5 c, 5 d and 5 e. If necessary, the substantially “U”-shaped pieces 5a, 5 b, 5 c, 5 d and 5 e further may be cut along a plane parallel withthe longitudinal direction and separated into substantially “L”-shapedor substantially flat pieces.

FIG. 4 shows an example in which the housing main body 3 iscut/processed and separated into substantially flat pieces of the topplate 4 a, the partition plates 4 c and 4 d, right side plates 6 a, 6 band 6 c and left side plates 7 a, 7 b and 7 c and a piece 9 formed ofthe bottom plate 4 b and a back plate 8 connected to have asubstantially-“L” shape.

FIG. 5 shows an example in which the substantially “L”-shaped piece 9shown in FIG. 4 is separated into the bottom plate 4 b and the backplate 8 that are substantially flat.

The following is a description of a device and a method for cutting andseparating the heat-insulating housing 1 into the plurality of pieces asabove.

Conventionally, for example, sheet steel pieces (cold-rolled steelsheets or the like) are cut generally by a band-shaped cutter (a bandsaw machine) or a disc-shaped cutter (a metal slitting saw), which isprovided with a high hardness saw blade, by grinder cutting using agrinding tool in which abrasive grains are formed in a disc shape or ina cylindrical shape, or by gas cutting using an acetylene gas or thelike.

Also, resin-molded articles are cut generally by a band saw machine, ametal slitting saw, an end mill, or the like.

Furthermore, a cutting method of using a diamond wheel cutter that isrotated at a high speed sometimes is employed.

However, the conventional cutting methods described above respectivelyhave the following problems.

When the sheet steel pieces are cut using a tool such as a band sawmachine or a metal slitting saw, a cutting blade of the tool is pressedstrongly against an object to be cut to cause a continuous shearfracture in the object to be cut, thus cutting/processing this object.Since the cutting blade is pressed strongly against the object to becut, frictional heat is generated greatly at the cutting part.Therefore, the embrittlement and enfeeblement of its cutting edge due tothe heat aggravate the abrasion of the cutting edge. Due to the abrasionof the cutting blade, the cutting speed is lowered considerably and thusis limited. In addition, since the cutting blade is allowed to bite intothe object to be cut, a high stiffness is needed for holding the tool (acutter) and the object to be cut, thus requiring a large-scale holdingmechanism and a high equipment cost.

When a blade made of a material containing a ferroalloy as a mainconstituent is used in cutting a metallic magnetic component, thefragments and powder that are produced by cutting an object to be cutare magnetic substances and thus adhere to the edge of the blade.Consequently, the increase in frictional resistance or the damage of theedge lowers the cutting performance of the blade considerably.

The grinder cutting using a grindstone is carried out by causingcontinuous small shears by cutting surfaces of the abrasive grains.Since the corners (cutting blades) of the abrasive grains are not sosharp and the peripheral speed of the grinder is relatively high, thefrictional heat generated at the cutting part is great. In order tosecure the lifetime of the grindstone, it is necessary to control thetemperature of the cutting part appropriately. Thus, the cutting speedis limited.

In the gas cutting using a gas such as acetylene, the cutting speed isslow, and it is important in view of safety that no combustibles bepresent in the vicinity of the cutting section. Therefore, this methodis not suitable for cutting a heat-insulating housing of a refrigeratorincluding a resin plate and a urethane heat insulator.

In the case of using a band saw machine, a metal slitting saw, or thelike for cutting resin-molded articles, when the cutting speed israised, the vicinity of the cutting part of an object to be cut startsburning or melts due to the frictional heat generated by the frictionwith the tool, thus causing a change in physical properties of theobject.

In the cutting method using a diamond wheel cutter, when the cuttingspeed is raised, the wear rate of the diamond wheel cutter increases dueto frictional heat and therefore the cutting speed is limited. Inaddition, the diamond wheel cutter is expensive, and the cutting amountand the wear rate of the diamond wheel have a close relationship,resulting in high cutting cost.

Moreover, a heat-insulating housing of a refrigerator generally isformed of a layered body including a steel plate, a heat insulator and aresin plate. Thus, it is extremely difficult to cut such an objectformed of a plurality of members with different physical propertiescontinuously using the same tool.

Furthermore, there are various types of discarded refrigerators, and theheat-insulating housings thereof also are formed of various kinds ofmaterials. Although main components such as a compressor already areremoved in advance, a component sometimes is attached at a position thatcannot be seen from the outside. When the information required forcutting/processing an object (physical properties or the like) isunknown or when an object to be cut is formed of a plurality of membersand the shapes and materials of the members hiding behind the surfacemember are unknown, it is difficult with the conventional cutting toolsto find out optimal cutting conditions merely from the image informationof the surface and outer shape of the object to be cut and to controlthe cutting automatically.

Furthermore, it is difficult to cut a heat-insulating housing formed ofmembers containing different materials such as sheet steel andresin-molded articles continuously one after another by rotating onekind of a conventionally-known cutting tool (a tool provided with acutting blade) or by moving it at a high speed.

Accordingly, as a method for cutting a heat-insulating housing of arefrigerator, the present invention provides a cutting method in which,instead of a conventional tool provided with a blade, an impacting bodyformed of a hard solid body such as metal is allowed to impact on theheat-insulating housing (an object to be cut, also referred to as “aworkpiece” in the following) at a very high speed with a high frequencyto generate a plastic wave by the impact energy, thus breaking andremoving the part subjected to the impact instantaneously.

This cutting method is obtained by putting a theory into practical useas a cutting device and a cutting method; the theory is a plastic wavetheory in which when a high-speed tensile force is applied at least at acritical impact velocity, a fracture occurs immediately at the partwhere the force has been applied, or a theory in which when a high-speedcompressive force is applied at least at a critical impact velocity, theductility is deteriorated rapidly and thus the part where the force hasbeen applied is broken even by a small distortion (a phenomenon similarto the embrittlement).

In other words, the cutting device and the cutting method of the presentinvention are based on the following principle: when an impacting bodythat executes a high speed circular motion impacts on a workpiece atleast at the critical impact velocity of the workpiece and then bounces(rebounds), the surface of the workpiece in a highly limited portionincluding the part subjected to the impact by the impacting body and itsvicinity is smashed (broken) instantaneously into a minute granularstate or minute fragments by a high speed compression that occurstogether with impact, a high speed tension due to friction, high speedshearing, or the like.

Generally, in processing a workpiece, external forces such as a tensileforce, a compressive force or a shearing force are applied to theworkpiece by the movement of a tool and thus the workpiece is distortedor deformed. In this case, when the speed of the tool, i.e., theprocessing speed is increased gradually and reaches a certainlimitation, the ductility of the workpiece deteriorates rapidly. Thislimitation speed is called the critical impact velocity. In theworkpiece, the part subjected to the force applied by a tool is brokenimmediately when the processing speed is increased to the criticalimpact velocity or more. When utilizing this, by allowing an impactingbody to impact on the workpiece at least at the critical impactvelocity, only the very surface portion of the workpiece that issubjected to the impact by the impacting body can be broken and removed.By setting the extremely large number of impacts by the impacting bodyper unit time, this phenomenon can be created repeatedly. Furthermore,by successively changing the position at which the impacting bodyimpacts, only the part on which the impacting body impacts can beremoved and processed successively without breaking the portion otherthan the part in the workpiece. Macroscopically, this can be consideredas cutting and processing of the workpiece. According to this cuttingmethod, a relatively smooth cut surface can be obtained.

In order to generate a plastic wave, the impacting body has to impact ona workpiece at least at the critical impact velocity of the workpiece.More specifically, in general, the impact velocity preferably is set tobe at least 139 m/second (about 500 km/hour), more preferably at least340 m/second (about 1224 km/hour).

When converted to the peripheral speed of a disc with a diameter of 100mm, the above-mentioned impact velocities correspond to rotationalspeeds of at least 26,500 rpm and of at least 65,130 rpm, respectively.

In practice, the critical impact velocity varies depending on the kindof a workpiece. For instance, the critical impact velocities ofaluminum, soft steel, stainless steel and titanium are about 49.7m/second, 30.0 m/second, 152.3 m/second, and 61.8 m/second,respectively. Therefore, the impact velocity of the impacting body canbe changed according to the kind of workpiece. The impact velocity ofthe impacting body preferably is set to be at least twice, furtherpreferably at least three times, and particularly preferably at leastfour times as high as the critical impact velocity of the workpiece,because this allows stable cutting.

The impacting body has a through hole and is maintained rotatably by aspindle provided perpendicularly on a rotor with a predetermined fittinggap being provided between the impacting body and the spindle. Byproviding the fitting gap, it is possible to absorb the displacement ofthe impacting body that occurs right after the impacting body hasimpacted on a workpiece. Preferably, the fitting gap between the spindlefor supporting the impacting body and the through hole of the impactingbody is set to be at least 2 mm, more preferably about 5 to 10 mm. It ispreferable that the fitting gap is designed to be larger along with anincrease in impact velocity of the impacting body. The fitting gapaccording to the present invention is far beyond the gap value accordingto the Japanese Industrial Standard (JIS), which generally defines thefitting state between an axis and a bearing, and is two to three ordersof magnitude larger than the gap value.

As described above, the processing principle of the present invention isdifferent from a conventional processing principle by utilizing impact.In the conventional processing principle, a cutting blade of a cuttingtool is allowed to collide with a workpiece at a low speed (a maximum ofabout 10 m/second) and the workpiece is deformed in a sequence fromelastic deformation through plastic deformation to breakage, thusbreaking the surface of the workpiece in a relatively large area.

The impacting body of the present invention is not provided with a sharpcutting blade as in the conventional cutting tool.

The cutting-according to the present invention based on theabove-mentioned principle is characterized as follows.

(1) According to the smashing (cutting) principle utilizing the highspeed compression and high speed tension at least at a critical impactvelocity when the impacting body impacts on a workpiece, an extremelysmall amount of the frictional heat only is generated at the part to becut in the workpiece. In addition, the impacting body is air-cooledrapidly by its quick movement and thus the increase in temperature ofthe impacting body itself also is extremely small.

(2) A conventional cutting tool that executes a rotational motion, areciprocating motion, or a rectilinear motion is heavily worn away. Onthe other hand, the impacting body of the present invention is subjectedto work hardening by the impact on a workpiece and therefore is hardenedas it is used, thus increasing its abrasion resistance.

(3) In the processing principle of the present invention, the cuttingresistance and the frictional resistance are low. As a result, aworkpiece does not have to be held and fixed firmly during cutting. Inaddition, it is not necessary to provide a high stiffness for a spindlefor supporting the impacting body, a rotor that rotates at a high speed,a main shaft, a bearing and a robot for holding the main shaft of therotor.

(4) By mounting an oscillation detector for detecting an intrinsicoscillatory waveform (or an intrinsic oscillation frequency), which isgenerated by a rotor depending on the nature of the workpiece whencutting the workpiece, on a multi-axis control robot, processingconditions (the impact velocity of the impacting body, the moving speed,etc.) can be controlled depending on the workpiece to be processed.

(5) Even when a workpiece is formed of a plurality of different members(for example, metal, a resin-molded article, glass or ferrite) and theinside of the workpiece cannot be seen from the outside, the workpiececan be cut continuously using the same cutting device.

As described above, the cutting device of the present invention has asimple configuration and can achieve an extended lifetime and aconsiderably improved reliability. In addition, since it is notnecessary to take into consideration during the cutting process thatdifferent materials may be intermixed in a workpiece, the cutting deviceof the present invention is extremely useful as a smashing or cuttingdevice that is a part of recycling equipment.

Using the cutting device described above makes it possible to automatedisassembling and cutting processes of a refrigerator for the purpose ofdisposal, and eliminates the need for changing the type of cutting tool,processing conditions or a cutting device according to the kind of aheat-insulating housing and components. In addition, the presentinvention contributes to the improvement in reliability, the extensionof lifetime of the cutting device, the increase in recycling ratio, theenvironmental protection, and the efficient use of natural resources.

In the following, an example of a specific configuration of theabove-described cutting device will be described, with reference to theaccompanying drawings.

(Embodiment B-1)

FIG. 6 is a sectional front view (a sectional view taken along the lineVI—VI in FIG. 7) showing a cutting device according to Embodiment B-1 ofthe present invention, FIG. 7 is a sectional side view, which is takenalong the line VII—VII in the cutting device shown in FIG. 6, FIG. 8 isa sectional front view showing the state of cutting a workpiece by usingthe cutting device shown in FIG. 6, and FIGS. 9A and 9B are viewsshowing an impacting body constituting the cutting device shown in FIG.6, with FIG. 9A being a front view and FIG. 9B being a sectional viewtaken along the line 9B—9B in FIG. 9A seen in an arrow direction.

As shown in FIGS. 6 to 8, a cutting device 10 according to EmbodimentB-1 includes a rotating unit 15 having a pair of discs (rotors) 11, 11that are spaced at a predetermined distance and attached to a main shaft12 with their principal planes opposing each other, and impacting bodies(hard solid bodies) 20 mounted rotatably to spindles 13 provided betweenthe pair of discs (rotors) 11, 11. The main shaft 12 is connected to arotating shaft of a driving motor, which is not shown in the figure, andthe rotating unit 15 is rotated about the main shaft 12 at a high speedto allow the impacting bodies (hard solid bodies) 20 to impact on aworkpiece (a heat-insulating housing) 90 at least at the critical impactvelocity of the workpiece 90. In the case where the workpiece 90 isformed of a layered body including a steel plate layer 91, a urethanefoam layer (a heat insulator) 92 and a resin plate layer 93 as shown inFIG. 8, the impacting bodies 20 are allowed to impact at least at thelargest critical impact velocity among those of these layers, namely,the critical impact velocity of the steel plate layer 91. With respectto the rotational speed, a variation of about ±10% is allowable due tothe variation in power supply voltage or other reasons.

The impact velocity of the impacting bodies 20 against the workpiece 90naturally corresponds to the rotational speed of the pair of discs(rotors) 11. The present embodiment employs a rotational speed in a highrotational speed range of 10,000 to 60,000 rpm as the rotational speedof the pair of discs (rotors). The high rotational speed range enablesthe impact force of the impacting bodies 20 to increase and the lifetimethereof to be extended by an air-cooling effect and work hardening.

In the cutting device 10 shown in FIG. 6, four impacting bodies 20 witha planar shape of cruciform are spaced equally between the principalplanes of the discs 11. As shown in FIGS. 9A and 9B, each of theimpacting bodies 20 with a planar shape of cruciform is provided withfour rectangular projections 21, which are spaced at equal angles, onthe peripheral surface of a cylindrical body 22 having a through hole23. The rectangular projections 21 correspond to cutting blades in aconventional tool and impact on the workpiece. As is apparent from FIG.6, each of the impacting bodies 20 is positioned so that a part (eachrectangular projection, i.e., each cutting blade 21) of its periphery islocated beyond the periphery of the discs 11.

Since four impacting bodies 20 are spaced equally between the principalplanes of the discs 11, the impacting frequency against the workpiece isat least (10,000 rotations/minute)×four impacting bodies=40,000times/minute.

A predetermined fitting gap 14 is provided between the spindle 13 andthe through hole 23 of the impacting body 20. By providing the fittinggap 14, the impacts on the cutting blades 21 of the impacting bodies 20and the spindles 13 are relieved although the rotors 11 rotate at a highspeed, thus preventing the spindles or the like in the cutting device 10from being damaged.

Besides the disc type, the rotors 11 may have an arbitrary shape such asa regular polygon. However, as a matter of course, the rotors should bebalanced during rotation.

Next, examples of dimensions and materials of the rotors and theimpacting bodies are described. In the device according to theembodiment shown in FIG. 6, the disc 11 had a diameter of 100 mm and aplate thickness of 5 mm and was made of carbon steel for machinestructural use, the spindle 13 had a diameter of 10 mm and was made ofcarbon steel for machine structural use or carbon tool steel (JIS code:SK2), the impacting body 20 had a distance L between top parts of twocutting blades of about 42 mm, the through hole 23 with a diameter of 17mm, the cutting blade 21 with a width W of about 15 mm and a thickness tof about 5 mm and was made of any one material selected from carbonsteel for machine structural use (S45C), carbon tool steel (SK2), highspeed tool steel (SKH2), Ni—Cr steel (SNC631), Ni—Cr—Mo steel (SNCM420),Cr—Mo steel (SCM430), chromium steel (SCr430) and manganese steel formachine structural use (SMn433).

In the example of cutting a workpiece, which is shown in FIG. 8, thedisc 11 was rotated at 30,000 rpm in the direction indicated by an arrow17. The impact velocity of the impacting bodies 20 against the workpiece(the layered body of a 1-mm-thick cold-rolled steel sheet 91, a4-mm-thick urethane foam 92 and a 1-mm-thickABS resin(acrylonitrile-butadiene-styrene copolymer) 93) 90 with a totalthickness of 6 mm was set to be about 157 m/second (565 km/hour) and themoving speed for cutting to be 100 mm/second. The cutting direction wasthe direction indicated by an arrow 18. In this case, the impactingfrequency was (30,000 rotations/minute)×four impacting bodies=120,000times/minute.

Since the main shaft 12 rotates at a high speed as described above, agreat centrifugal force acts on the impacting bodies 20. The centrifugalforce causes a high-speed compressive force accompanied with impacts ina limited portion of the workpiece 90 including the surface subjected tothe impact by the cutting blades 21 of the impacting bodies 20 and thevicinity of the impact surface. Thus, the top layer of the impactsurface of the workpiece 90 is smashed at a high speed instantaneously.Cut scraps are in a minute granular state. It has been confirmed by atest that the workpiece can be cut even when no sharp cutting blade isprovided.

In the above, the impact velocity of the impacting bodies 20 is notlimited to the above-mentioned specific example and can be set freelydepending on the kind of a workpiece, cutting conditions, or the like aslong as the impact velocity is at least the critical impact velocity ofthe workpiece. Similarly, the number of impacts by the impacting bodies20 per unit time also can be changed depending on the kind of aworkpiece, cutting conditions, or the like.

When the material of a workpiece is unknown, when a workpiece is formedof a plurality of different kinds of members, or when a member whosematerial is unknown hides in a part that cannot be seen from theoutside, such a workpiece can be cut excellently by setting the impactvelocity of the impacting bodies to be somewhat higher.

With respect to the material for the impacting bodies 20, members otherthan metallic members also can be used freely as long as they are hardsolid bodies.

The number of the rectangular projections (cutting blades) 21 providedin the impacting body 20 is not limited to four as shown in FIGS. 9A and9B, but may be smaller (two or three) or larger (five or six, forexample).

Furthermore, the number of the impacting bodies 20 may be only one or atleast two. In the case of providing a plurality of the impacting bodies,it is preferable to provide them at equal angles with respect to therotational center of the rotors, because this results in equal impactintervals to enable stable cutting. In the case of using only oneimpacting body, a balancer (a weight) is provided to secure therotational balance.

Instead of spacing the pair of rotors 11 so as to arrange the impactingbodies therebetween, only one rotor may be used with the spindlesprovided on one side thereof perpendicularly thereto with a cantileveredsupport structure, so that the impacting bodies may be provided on thesespindles.

The rotor may be driven to rotate at a high speed using a generalspindle motor or the like.

The impacting bodies 20 of the present embodiment are not provided withsharp cutting blades as in a conventional cutting tool. The cuttingprinciple of the present embodiment goes beyond a conventional practicalsense and enables even brittle members such as metal, resin, glass,ceramics, or the like to be cut without using sharp cutting blades byproviding the impacting bodies 20 with a far higher speed than that in aconventional cutting tool.

(Embodiment B-2)

FIG. 10 is a top view showing a cutting device according to EmbodimentB-2 of the present invention, and FIG. 11 is a sectional view thereoftaken along the line XI—XI in FIG. 10 seen in an arrow direction,showing the state of cutting a workpiece as well.

A cutting device 100 in Embodiment B-2 has a first rotating unit 110 anda second rotating unit 120 as shown in FIGS. 10 and 11.

The first rotating unit 110 has a pair of discs (rotors) 111, 111 thatare spaced at a predetermined distance and attached to a main shaft 112with their principal planes opposing each other, and impacting bodies(hard solid bodies) 130 mounted rotatably to spindles 113 providedbetween the pair of discs 111, 111. The main shaft 112 is connected to arotating shaft of a driving motor 115, so that the first rotating unit110 is rotated about the main shaft 112 serving as a rotational center.Four spindles 113 are provided on the circumference of a circle, whosecenter corresponds to this rotational center, in such a manner as to bespaced at equal angles.

Similarly, the second rotating unit 120 has a pair of discs (rotors)121, 121 that are spaced away at a predetermined distance and attachedto a main shaft 122 with their principal planes opposing each other, andimpacting bodies (hard solid bodies) 140 mounted rotatably to spindles123 provided between the pair of discs 121, 121. The main shaft 122 isconnected to a rotating shaft of a driving motor 125, so that the secondrotating unit 120 is rotated about the main shaft 122 serving as arotational center. Four spindles 123 are provided on the circumferenceof a circle, whose center corresponds to this rotational center, in sucha manner as to be spaced at equal angles.

The first rotating unit 110 and the second rotating unit 120 are held bya common base 103 so that the directions of the axes of rotation thereofare parallel and the principal planes of the discs 111 and the discs 121are on substantially the same plane, in other words, so that a circularpath 117 of cutting blades 131 at the tip of the impacting bodies 130and a circular path 127 of cutting blades 141 at the tip of theimpacting bodies 140 during the rotation substantially are on the sameplane. The base 103 is mounted on a robot arm 251.

FIGS. 12A and 12B show a specific configuration of the impacting body130. FIG. 12A is a front view, and FIG. 12B is a side view. As shown inthese figures, the square impacting body 130 has a shape such as the oneobtained by attaching a cylindrical body 132 with a through hole 133 tothe central portion of a plate member with a planar shape of a squareand a predetermined thickness. The cylindrical body 132 is made to havea length larger than the thickness of the square plate member, thussecuring mechanical strength. Four corners 131 of the square platemember correspond to cutting blades in a conventional tool and impact onthe workpiece. The impacting body 130 is attached to the rotating unit110 by passing the spindle 113 through the through hole 133. As shown inFIGS. 10 and 11, the impacting body 130 is attached so that a part ofits periphery (in particular, the cutting blade 131) is located beyondthe periphery of the disc 111 when the rotating unit 110 rotates. In thedevice shown in FIGS. 10 and 11, four impacting bodies 130 are arrangedon the principal planes of the discs 111 so as to be spaced equally fromeach other.

FIGS. 13A and 13B show a specific configuration of the impacting body140. FIG. 13A is a front view, and FIG. 13B is a side view. As shown inthese figures, the substantially bow-shaped impacting body 140 has afloating portion 145, a through hole 143 provided at one end of thefloating portion 145 and the cutting blade 141 provided at the other endof the floating portion 145. The floating portion 145 has a shapeapproximate to a substantially-bow shape that is formed of asubstantially circular-arc portion and a chord extending between bothends of the circular-arc, or a substantially-bow shape that issubstantially the same as that of pieces obtained by bisecting anellipse or an oval along its longitudinal direction. The cutting blade141 is formed to be thick so as to be resistant to shock at the time ofimpacting on the workpiece, the peripheral portion of the through hole143 is formed to be thick so as to be resistant to centrifugal forceduring rotation, and other portions are formed to be thin so as toreduce weight. The impacting body 140 is attached to the rotating unit120 with its cutting blade 141 facing forward in the rotationaldirection by passing the spindle 123 through the through hole 143. Asshown in FIGS. 10 and 11, the impacting body 140 is attached so that apart of its periphery (in particular, the cutting blade 141) is locatedbeyond the periphery of the disc 121 when the rotating unit 120 rotates.In the device shown in FIGS. 10 and 11, four impacting bodies 140 arearranged on the principal planes of the discs 121 so as to be spacedequally from each other. The planar shape of the through hole 143preferably is an ellipse as shown in FIGS. 13A and 13B. More accurately,the planar shape of the through hole 143 is a circular-arc ellipticalshape that is formed by two circular arcs with different radii whosecenters are the center of gravity of the impacting body 140 andsemicircles connecting both ends of these two circular arcs in thecircumferential direction. By forming the through hole 143 to be acircular-arc elliptical hole whose center is the center of gravity ofthe impacting body 140, the displacement of the impacting body 140 whenthe impacting body 140 rebounds in such a manner as to rotate about itscenter of gravity after impacting on a workpiece can be absorbed well,thus improving the cutting performance. Since a rotationally symmetricimpacting body such as the impacting body 130 shown in FIGS. 12A and 12Bhas a center of gravity substantially corresponding to the center of thethrough hole 133, the planar shape of the through hole 133 is formed tobe circular, thereby absorbing the above-mentioned displacement causedby the rebound at the time of impacting.

A predetermined fitting gap 114 is provided between the spindle 113 andthe through hole 133 of the impacting body 130. Similarly, apredetermined fitting gap 124 is provided between the spindle 123 andthe through hole 143 of the impacting body 140. By providing the fittinggaps 114, 124, the impacts on the cutting blades 131, 141 and thespindles 113, 123 are relieved when the impacting bodies impact on theworkpiece even though the rotors 111, 121 rotate at a high speed, thuspreventing components of the rotating units 110, 120 such as thespindles from being damaged.

The following is a description of an example of cutting a workpiece byusing the above-described cutting device 100. The description isdirected to the case of cutting a workpiece (a heat-insulating housing)290 having a layered structure including a steel plate layer 291, aurethane foam layer (a heat insulator) 292 and a resin plate layer 293in this order as shown in FIG. 11. The cutting device 100 and theworkpiece 290 are arranged such that the directions of the axes ofrotation of the main shafts 112, 122 are substantially parallel with asurface of the plate-like workpiece 290. Then, the cutting device 100 ismoved in the direction indicated by an arrow 109 while rotating thefirst rotating unit 110 and the second rotating unit 120 at a high speedin the directions indicated respectively by arrows 119, 129. The movingdirection 109 is parallel with the principal planes of the discs 111,121 and with the surface of the workpiece 290. Accordingly, theimpacting bodies 130 of the first rotating unit 110 first impact on thesteel plate layer 291 on the surface of the workpiece 290, and the steelplate layer 291 and a part of the upper portion of the urethane layer292 are cut, so that a groove having a predetermined width and depth isformed on the upper surface of the workpiece 290. Subsequently, theimpacting bodies 140 of the second rotating unit 120 advance along thisgroove, thus cutting the lower portion of the urethane layer 292 and theresin plate layer 293, which have not been subjected to the impactingbodies 130.

At this time, the rotating units are rotated so that at least either ofthe impacting bodies 130 or the impacting bodies 140 impact on theworkpiece at least at the critical impact velocity of the workpiece 290.In the above example, it is preferable that the impacting bodies 130impacting on the steel plate layer 291, which is made of a high hardnessmaterial and difficult to cut, impact at least at the critical impactvelocity of a material of the steel plate layer 291. With respect to therotational speed, a variation of about ±10% is allowable due to thevariation in power supply voltage or other reasons.

The impact velocity of the impacting bodies 130 against the workpiece290 naturally corresponds to the rotational speed of the pair of discs(rotors) 111. The present embodiment employs a rotational speed in ahigh rotational speed range of, for example, 10,000 to 60,000 rpm as therotational speed of the pair of discs 111. The high rotational speedrange enables the impact force of the impacting bodies 130 to increaseand the lifetime thereof to be extended by an air-cooling effect andwork hardening. In the cutting device 100 shown in FIG. 11, fourimpacting bodies 130 are spaced equally between the principal planes ofthe discs 111. Therefore, the impacting frequency of the first rotatingunit 110 against the workpiece 290 is at least (10,000rotations/minute)×four impacting bodies=40,000 times/minute.

In the above example, the impacting bodies 140 of the second rotatingunit 120 need not be allowed to impact at least at the critical impactvelocity of the workpiece 290 (in particular, the urethane layer 292 andthe resin plate layer 293). Since the urethane layer 292 and the resinplate layer 293 have a low hardness and do not cause a brittle fractureeasily, even when the impacting bodies 140 are allowed to impact at thecritical impact velocity of the workpiece or lower, only the vicinity ofthe part subjected to the impact is smashed and can be cut easily. Insuch cases, it may be possible to choose to rotate the rotating unit 120not at a high speed but at a low speed, thereby saving a driving energy.This also eliminates the need for the design that is resistant to agreat centrifugal force generated at the time of high-speed rotation,making it possible to reduce the size and weight of the second rotatingunit 120 and improve safety. Also, it becomes possible to reduce thesize of the driving motor 125. In this way, equipment cost and runningcost can be reduced. Of course, there are some cases where, depending ona material of the layer to be cut mainly by the impacting bodies 140 ofthe second rotating unit 120, the impacting bodies 140 preferably areallowed to impact at least at the critical impact velocity of thismaterial.

As described above, in the cutting device 100 of the present embodiment,the impacting bodies 130 of the first rotating unit 110 cut only the toplayer of the workpiece 290, and the impacting bodies 140 of thefollowing second rotating unit 120 cut deeply to the back surfacethereof. In the present embodiment, in order that the impacting bodiesof these rotating units have different cutting depths, the circularpaths 117, 127 of the tips of the cutting blades of the impacting bodiesof these rotating units are made to have different radii and the mainshafts 112, 122 are made to have different heights above (distancesfrom) the surface of the workpiece 290 as shown in FIG. 11. Simplychanging the heights of the axes of rotation (the main shafts) of theserotating units while keeping their configurations completely the samealso can change the cutting depths of the impacting bodies of theserotating units. However, there are some cases where the circular path117 of the first rotating unit 110 preferably is designed to have asmaller radius than the circular path 127 of the second rotating unit120 by modifying the shapes of the impacting bodies as described in thepresent embodiment. The reason follows. In order to allow the impactingbodies to impact on the workpiece at least at the critical impactvelocity, the rotating unit has to be rotated at a high speed. On theother hand, in order to cut the workpiece having a certain thickness,the projecting length of the impacting bodies beyond the disc duringrotation has to be longer than the thickness of the workpiece. Thus,there is a lower limit of the size of the impacting body. When a largeimpacting body is attached to the rotating unit, the weight of theimpacting body and the distance from the rotational center to the centerof gravity of the impacting body increase. Therefore, as the impactingbody becomes larger, the centrifugal force generated at the time ofhigh-speed rotation increases in an accelerating manner. As a result, itbecomes necessary to design the device having a mechanical strength thatcan withstand this centrifugal force, leading to a further increase inweight and costs. Accordingly, when cutting the workpiece 290 having alayered structure and whose surface and back layers have differentcritical impact velocities as in the above example, the workpiece isdisposed so that the steel plate layer 291 having a large criticalimpact velocity can be cut first and the circular path 117 of the firstrotating unit 110 cutting the steel plate layer 291 is made to besmaller than the circular path 127 of the second rotating unit 120.Consequently, the size of the impacting bodies 130 of the first rotatingunit 110 can be reduced, and thus their radius of gyration alsodecreases, thus realizing a high-speed rotation of the first rotatingunit 110 easily. On the other hand, since the rotational speed of thesecond rotating unit 120 cutting the urethane layer 292 and the resinplate layer 293 having a relatively small critical impact velocity canbe made lower than that of the first rotating unit 110, the strengthdesign can be carried out relatively easily even when providing largeimpacting bodies 140. Because a heat-insulating housing of arefrigerator usually has a steel plate as an outer wall plate and aresin plate as an inner wall plate, the cutting device of the presentembodiment is used to cut/process the housing from outside, thusallowing the cutting as illustrated in FIG. 11.

The cutting device of Embodiment B-2 includes at least two rotatingunits. This has the following effects compared with the device ofEmbodiment B-1, which cuts the workpiece at one time with only a singlerotating unit. For example, when the workpiece is thick, the projectinglength of the impacting bodies beyond the disc at the time of rotationhas to be greater than the workpiece thickness in order to cut theworkpiece at one time with only one rotating unit. This increases thesize and weight of the impacting bodies. In order to rotate them at ahigh speed, the mechanical strength needs to be improved, leading to anincrease in the weight of the rotating unit and higher costs asdescribed above. Also, when cutting the workpiece formed by layeringdifferent kinds of materials, the impacting bodies have to be allowed toimpact at least at the largest critical impact velocity among those ofthe layered materials in order to cut the workpiece at one time withonly one rotating unit. Thus, it is necessary to rotate the rotatingunit at a high speed, and therefore, the strength design and drivingmechanism of the rotating unit have to be brought into correspondencewith such a rotation, which brings about much waste. Furthermore, whenattempting to cut the workpiece 290 at one time with only the secondrotating unit 120 provided with, for example, the substantiallybow-shaped impacting bodies 140 with longer projecting lengths, theimpact on the difficult-to-machine steel plate layer 291 causes eachimpacting body 140 to rebound and rotate about the spindle 123 and theninterfere with the impacting body 140 positioned toward the back in therotational direction, which is supposed to impact on the workpiecesubsequently. Also, when the workpiece is thick, the speed of theimpacting body lowers at some midpoint in the thickness direction of theworkpiece, and then this impacting body interferes with the subsequentimpacting body 140 within the workpiece. Such interferences between theimpacting bodies deteriorate the cutting efficiency and the reliabilityof the cutting device. When the intervals between the impacting bodiesare increased for the purpose of preventing the interferencetherebetween, the number of the impacting bodies declines, leading tofewer impacting times and lower cutting efficiency. For the abovereasons, the workpiece is cut by sequentially increasing the cuttingdepth using a plurality of the cutting units, thereby achieving anexcellent cutting performance with respect to a thick workpiece and aworkpiece formed by layering different kinds of materials. As becomesclear from the above, when the workpiece is relatively thin, it is ofcourse possible to cut the workpiece at one time with only a singlerotating unit illustrated in Embodiment B-1.

Besides the disc type, the rotors 111, 121 may have an arbitrary shapesuch as a regular polygon. However, as a matter of course, the rotorsshould be balanced during rotation.

Next, examples of dimensions and materials of the rotors and theimpacting bodies are described. In the cutting device according to theembodiment shown in FIGS. 10 and 11, the disc 111 had a diameter of 100mm and a plate thickness of 5 mm and was made of carbon steel formachine structural use, and the disc 121 had a diameter of 200 mm and aplate thickness of 10 mm and was made of carbon steel for machinestructural use. The spindle 113 had a diameter of 10 mm and was made ofcarbon steel for machine structural use or carbon tool steel (JIS code:SK2), and the spindle 123 had a diameter of 21 mm and was made of carbonsteel for machine structural use or carbon tool steel (JIS code: SK2).The impacting body 130 had a 34.2 mm×34.2 mm square plate member with athickness of 5 mm, the cylindrical body 132 with an outer diameter of 25mm and a length of 10 mm and the through hole 133 with an inner diameterof 17 mm. The impacting body 140 had a total length L0 of 200 mm, alength L1 from substantially the center of the through hole 143 to theend of the cutting blade 141 of 160 mm, the through hole 143 thereof hadan inner dimension along its lengthwise direction of 26 mm and thatalong its widthwise direction of 22 mm, and the cutting blade 141, theperipheral portion of the through hole 143 and the other portions had athickness of 6 mm, 10 mm and 5 mm, respectively, as shown in FIGS. 13Aand 13B. The impacting bodies 130 and 140 were made of any one materialselected from carbon steel for machine structural use (S45C), carbontool steel (SK2), high speed tool steel (SKH2), Ni—Cr steel (SNC631),Ni—Cr—Mo steel (SNCM420), Cr—Mo steel (SCM430), chromium steel (SCr430)and manganese steel for machine structural use (SMn433).

In the example of cutting a workpiece, which is shown in FIGS. 10 and11, the disc 111 was rotated at 30,000 rpm in the direction indicated byan arrow 119, and the impact velocity of the impacting bodies 130against the steel plate layer 291 (a 1-mm-thick cold-rolled steel sheet)as the top layer of the workpiece 290 was set to be about 157 m/second(565 km/hour). Also, the disc 121 was rotated at 3000 rpm in thedirection indicated by an arrow 129, and the impact velocity of theimpacting bodies 140 against the urethane layer 292 (a 60-mm-thickurethane foam) and the resin plate layer 293 (a 1-mm-thick ABS resin(acrylonitrile-butadiene-styrene copolymer)) of the workpiece 290 wasset to be about 72 m/second (260 km/hour). The workpiece 290 was fixed,and the robot arm 251 is controlled to move the cutting device 100 atthe moving speed for cutting of 50 mm/second in the direction indicatedby an arrow 109. In this case, the impacting frequencies were (30,000rotations/minute)×four impacting bodies=120,000 times/minute for theimpacting bodies 130 and (3,000 rotations/minute)×four impactingbodies=12,000 times/minute for the impacting bodies 140.

Since the main shaft 112 rotates at a high speed as described above, agreat centrifugal force acts on the impacting bodies 130. Thecentrifugal force causes a high-speed compressive force accompanied withimpacts in a limited portion of the steel plate layer 291 including thesurface subjected to the impact by the cutting blades 131 of theimpacting bodies 130 and the vicinity of the impact surface. Thus, thetop layer of the impact surface of the steel plate layer 291 is smashedat a high speed instantaneously. Cut scraps are in a minute granularstate. It has been confirmed by a test that the workpiece can be cuteven when no sharp cutting blade is provided.

The impact velocity of the impacting bodies 140 against the urethanelayer 292 and the resin plate layer 293 are not greater than thecritical impact velocity of materials for these layers. Even when theimpacting bodies 140 are allowed to impact on these layers at theircritical impact velocity or lower, unlike the case of thedifficult-to-machine iron layer, only the vicinity of the part subjectedto the impact is smashed and the fracture does not propagate widely.Thus, the workpiece 290 can be cut substantially along the groove formedby the impacting bodies 130.

In the above, the impact velocities of the impacting bodies 130, 140 arenot limited to the above-mentioned specific example and can be setfreely depending on the kind of a workpiece, cutting conditions, or thelike as long as at least either of them is at least the critical impactvelocity of the workpiece (when the workpiece is formed of a layeredbody including a plurality of layers, the impact velocity of theimpacting bodies cutting the layer that is most difficult to cut in viewof physical properties such as hardness, brittleness and strength isconsidered to be at least at the critical impact velocity of thematerial for this layer). Similarly, the number of impacts by theimpacting bodies 130, 140 per unit time also can be changed depending onthe kind of a workpiece, cutting conditions, or the like.

When the material of a workpiece is unknown, when a workpiece is formedof a plurality of different kinds of members, or when a member whosematerial is unknown hides in a part that cannot be seen from theoutside, such a workpiece can be cut excellently by setting the impactvelocity of the impacting bodies to be somewhat higher.

With respect to the material for the impacting bodies, members otherthan metallic members also can be used freely as long as they are hardsolid bodies.

Furthermore, the number of the impacting bodies provided in one rotatingunit may be only one or at least two. In the case of providing aplurality of the impacting bodies, it is preferable to provide them atequal angles with respect to the rotational center of the rotors,because this results in equal impact intervals to allow stable cutting.In the case of using only one impacting body, a balancer (a weight) isprovided to secure the rotational balance.

It is preferable that the cutting blade of the impacting body providedin the following rotating unit is designed to have substantially thesame thickness as or to be thinner than that provided in the foregoingrotating unit, which cuts into the workpiece earlier. By cutting intothe workpiece with the impacting bodies having the same thickness orwith decreasing thickness, the following impacting bodies reliably canfit into a groove-like incised portion formed on the workpiece by theforegoing impacting bodies.

Moreover, instead of spacing the pair of rotors so as to arrange theimpacting bodies therebetween, only one rotor may be used with thespindles provided on one side thereof perpendicularly thereto with acantilevered support structure, so that the impacting bodies may beprovided on these spindles.

The rotor may be driven to rotate at a high speed using a generalspindle motor or the like.

The number of the rotating units is not limited to two as describedabove but may be three or more. If three or more rotating units are usedand the workpiece is cut sequentially by increasing the cutting depth ofthe impacting bodies of these units as described above, such a workpiececan be cut excellently even when the workpiece is thick or has amultilayered structure. In such cases, it is preferable that theimpacting bodies of these rotating units are allowed to impact on theworkpiece at least at the critical impact velocity of each material ofthe workpiece to be cut by the respective units. However, as is alreadymentioned, there are some cases where, depending on a material of theworkpiece, the workpiece can be cut without any problems even when notall the impacting bodies of a plurality of the rotating units is allowedto impact at least at the critical impact velocity.

For example, when the steel plate layer 291 as the top layer of theworkpiece 290 is thick and thus the entire thickness thereof isdifficult to cut at one time with the first rotating unit in the aboveexample, a third rotating unit that has substantially the sameconfiguration with the first rotating unit is provided between the firstrotating unit and the second rotating unit in the cutting device shownin FIGS. 10 and 11. Then, the cutting depth is increased in the order ofthe first, third and second rotating units, thus cutting the steel platelayer 291 with the first rotating unit and the third rotating unit. Inthis case, it is needless to say that the impacting bodies of the firstand third rotating units preferably are allowed to impact on the steelplate layer 291 at least at the critical impact velocity of the steelplate layer 291.

The plurality of the rotating units constituting the cutting device donot have to be attached to the common base as in the above example, butmay be supported and moved individually so as to move along cuttingpositions on the workpiece sequentially. However, when they are mountedon the common base, it is possible to control the movement of thecutting device as one piece, allowing a simplification of equipment andconst reduction.

In addition, although the workpiece was cut by moving the cutting devicewhile fixing the workpiece in the above example, it also may be cut bymoving the workpiece while fixing the cutting device at a predeterminedposition.

As described above, the impacting bodies of the present embodiment arenot provided with sharp cutting blades as in a conventional cuttingtool. The cutting principle of the present embodiment goes beyond aconventional practical sense and enables even brittle members such asmetal, resin, glass, ceramics, or the like to be cut by a single cuttingdevice without using sharp cutting blades by providing the impactingbodies with a far higher speed than that in a conventional cutting tool.

(Embodiment B-3)

Impacting bodies to be attached to the cutting devices described inEmbodiments B-1 and B-2 are not limited to those shown in FIGS. 9A and9B, FIGS. 12A and 12B and FIGS. 13A and 13 b, but can be those withvarious shapes. In the following, examples of usable shapes of impactingbodies will be described.

FIGS. 14A and 14B show a modified cruciform impacting body as anotherexample of an impacting body having projections at substantially equalangles on its periphery as shown in FIGS. 9A and 9B, with FIG. 14A beinga front view and FIG. 14B being a side view. A modified cruciformimpacting body 160 is formed by modifying the shape of the rectangularprojections 21 in the cruciform impacting body 20 shown in FIGS. 9A and9B. In other words, the modified cruciform impacting body 160 has foursubstantially parallelogram projections 161, which are spaced at equalangles in a circumferential direction, on the peripheral surface of acylindrical body 162 having a through hole 163. The projections 161 areattached so that an acute end 161 a on a periphery of each projection161 faces the direction of impacting on the workpiece. The number of thesubstantially parallelogram projections 161 is not limited to four as inthe present example but may be less (two, three) or more (for example,five, six). Also, instead of the substantially parallelogram projections161, projections such as substantially triangle projections, arch-shapedprojections or substantially semicircular projections also may beprovided in such a manner as to be spaced away at equal angles.

FIGS. 15A and 15B show a disc-shaped impacting body 170, with FIG. 15Abeing a front view and FIG. 15B being a sectional view taken along theline 15B—15B in FIG. 15A seen in an arrow direction. The disc-shapedimpacting body 170 has a shape such as the one obtained by inserting acylindrical body 172 with a through hole 173 into the central portion ofa ring cutting blade 171 with a predetermined thickness.

FIGS. 16A and 16B show a regular-hexagonal impacting body, with FIG. 16Abeing a front view and FIG. 16B being a sectional view taken along theline 16B—16B in FIG. 16A seen in an arrow direction. Theregular-hexagonal impacting body 180 has a shape such as the oneobtained by inserting a cylindrical body 182 with a through hole 183into the central portion of a plate member with an outer shape ofregular hexagon and a predetermined thickness. Six corners 181 on theperiphery of the plate member serve as cutting blades. Instead of theregular hexagon, the plate member can have an outer shape of otherregular polygons such as a regular triangle, a regular pentagon and aregular octagon.

FIGS. 17A and 17B show a substantially bell-shaped impacting body, withFIG. 17A being a front view and FIG. 17B being a side view. Asubstantially bell-shaped impacting body 190 has a planar shape of abell shape or a suitable variation thereof. An end corresponding to theportion on which the bell is suspended is a cutting blade 191 forimpacting on the workpiece, and a wide region on the opposite side isprovided with a through hole 193 through which a spindle is passed.Furthermore, a through hole 194 is provided for reducing weight, and theregion in which the through hole 194 is formed is thinner than theregion in which the through hole 193 is formed.

FIGS. 18A and 18B show a modified pentagonal impacting body, with FIG.18A being a front view and FIG. 18B being a side view. A modifiedpentagonal impacting body 200 has a planar shape that is substantiallythe same as a pentagon obtained by cutting off corners on both sides onone shorter side of a rectangle. A resultant corner at the tip formed bycutting off the corners on the both sides is a cutting blade 201 forimpacting on the workpiece. On the opposite side, a through hole 203through which a spindle is passed is formed.

FIGS. 19A and 19B show a substantially “9”-shaped impacting body, withFIG. 19A being a front view and FIG. 19B being a sectional view takenalong the line 19B—19B in FIG. 19A seen in an arrow direction. Asubstantially “9”-shaped impacting body 210 has a substantiallydisc-shaped plate 216 having a substantially circular (or substantiallyoval) shape and a wedge-shaped portion 215, which are connected so as toform a substantially “9” shape or a substantially “,” (comma) shape. Anend of the wedge-shaped portion 215 is a cutting blade 211 for impactingon the workpiece. In addition, the substantially central portion of thesubstantially disc-shaped plate 216 is provided with a through hole 213through which a spindle is passed, and the periphery thereof is formedto be thick for raising mechanical strength. Furthermore, edge portionsof the substantially disc-shaped plate 216 and the wedge-shaped portion215 are formed to be thick and inner regions thereof are formed to bethin for reducing weight while maintaining the necessary mechanicalstrength.

FIGS. 20A and 20B show a substantially bow-shaped impacting body, withFIG. 20A being a front view and FIG. 20B being a side view. Asubstantially bow-shaped impacting body 220 shown in FIGS. 20A and 20Bis an example of modifying the substantially bow-shaped impacting body140 shown in FIGS. 13A and 13B. As the substantially bow-shapedimpacting body 140 shown in FIGS. 13A and 13B, the substantiallybow-shaped impacting body 220 has a substantially bow-shaped floatingportion 225, a through hole 223 having a circular-arc elliptical shapeprovided at one end of the floating portion 225 and a cutting blade 221provided at the other end of the floating portion 225. The substantiallybow-shaped impacting body 220 is different from the substantiallybow-shaped impacting body 140 shown in FIGS. 13A and 13B in thefollowing points. First, the peripheral region of the through hole 223through which a spindle is passed is formed to be still thicker, thusimproving a mechanical strength to resist a centrifugal force generatedat the time of rotation. Second, the floating portion 225 is providedwith through holes 224 so as to reduce weight, thus reducing thecentrifugal force generated at the time of rotation.

FIGS. 21A and 21B show another example of a substantially bow-shapedimpacting body, with FIG. 21A being a front view and FIG. 21B being aside view. A substantially bow-shaped impacting body 230 shown in FIGS.21A and 21B is an example of modifying the substantially bow-shapedimpacting body 140 shown in FIGS. 13A and 13B. The substantiallybow-shaped impacting body 230 has a floating portion 235 as thesubstantially bow-shaped impacting body 140 shown in FIGS. 13A and 13B,but a portion corresponding to the chord of the bow is bent in the samedirection as the substantially circular arc portion in the impactingbody 230, whereas it is a straight line in the impacting body 140 shownin FIGS. 13A and 13B. As in the substantially bow-shaped impacting body140 shown in FIGS. 13A and 13B, a through hole 233 having a circular-arcelliptical shape is formed at one end of the floating portion 235 and acutting blade 231 is formed at the other end of the floating portion235. In addition, as in the substantially bow-shaped impacting body 220shown in FIGS. 20A and 20B, the peripheral region of the through hole233 through which a spindle is passed is formed to be thick, thusimproving a mechanical strength to resist a centrifugal force generatedat the time of rotation.

The impacting body can have various shapes other than the above as longas it has a through hole through which a spindle can be passed and acutting blade to impact on the workpiece. Furthermore, the tips of thethrough hole and the cutting blade may be made thick for raising themechanical strength, while a through hole may be provided suitably orthe plate thickness may be reduced partially so as to reduce weight forthe purpose of reducing the centrifugal force generated at the time ofrotation.

Among the impacting bodies described above, impacting bodies that arerotationally symmetric with respect to an axis of the through holethrough which a spindle is inserted such as the impacting body 20 (FIGS.9A and 9B), the impacting body 130 (FIGS. 12A and 12B), the impactingbody 160 (FIGS. 14A and 14B), the impacting body 170 (FIGS. 15A and 15B)and the impacting body 180 (FIGS. 16A and 16B) have a smaller projectinglength beyond the rotor but can achieve lighter weight. Therefore, theycan be used suitably as an impacting body of a rotating unit rotating ata very high speed or a rotating unit that does not require a greatcutting depth (the first rotating unit 110 in the example of EmbodimentB-2). On the other hand, impacting bodies provided with a through holethrough which a spindle is inserted at one end of an oblong floatingportion such as the impacting body 140 (FIGS. 13A and 13B), theimpacting body 220 (FIGS. 20A and 20B) and the impacting body 230 (FIGS.21A and 21B) can achieve a larger projecting length beyond the rotor soas to obtain a greater cutting depth, but are a relatively heavy andhave the center of gravity far from an axis of rotation of the rotatingunit. Accordingly, the strength to withstand the centrifugal forcegenerated when rotating the unit at a very high speed has to beconsidered. Therefore, they can be used suitably as an impacting body ofa rotating unit rotating at a relatively low speed or a rotating unitthat requires a great cutting depth (the second rotating unit 120 in theexample of Embodiment B-2). Furthermore, the shapes of the impactingbody 190 (FIGS. 17A and 17B), the impacting body 200 (FIGS. 18A and 18B)and the impacting body 210 (FIGS. 19A and 19B) have intermediatecharacteristics between the above two groups and can be used for boththe first rotating unit 110 and the second rotating unit 120 in theexample of Embodiment B-2.

(Embodiment B-4)

FIGS. 22 and 23 both show the state of cutting a heat-insulating housingof a refrigerator by using cutting and processing equipment includingthe cutting device 10 illustrated in Embodiment B-1, with FIG. 22 beinga side view and FIG. 23 being a plan view. The cutting and processingequipment of the present embodiment has a configuration in which thecutting device 10 of Embodiment B-1 is mounted to the tip of a robotarm.

In FIGS. 22 and 23, numeral 3 indicates a housing main body of arefrigerator, which is an object to be cut/processed (a workpiece) (asshown in FIG. 2, doors already are removed), numeral 10 indicates thecutting device described in Embodiment B-1, numeral 250 indicates acommercially available robot controlled with five axes, numeral 260indicates a carrier pallet on which the housing main body 3 is loaded,and numeral 262 indicates a roller conveyor for carrying the carrierpallet 260. A driving motor 16 is attached to a jig at the tip of thearm of the robot 250, and its driving axis is connected with the mainshaft 12 of the cutting device 10 (see FIGS. 6 and 7).

When the housing main body 3 loaded on the carrier pallet 260 arrives infront of the five-axes controlled robot 250, which is detectedautomatically, the cutting device 10 mounted to the arm of the robot 250is rotated and driven. Thus, the housing main body 3 is cut andprocessed by the five-axes control function, for example, as describedin FIGS. 3 to 5.

The above-mentioned equipment preferably is provided with a followingcontrol device (not shown in the figure). The control device detects atleast one of an intrinsic oscillatory waveform and an intrinsicoscillation frequency that are caused by the impact of the impactingbodies of the cutting device 10 against the housing main body 3, theload on the driving motor 16 and an outer shape of the housing main body3 and controls and changes at least one of the rotational speed of therotating unit (the impact velocity of the impacting bodies) of thecutting device 10, a cutting depth and a relative speed (a feed speed)and a relative moving direction (for example, when the cutting is judgedto be difficult, the cutting device 10 is reversed slightly) between therotating unit and the housing main body 3. In this manner, even when thehousing main body 3 is formed of a plurality of members with differentphysical properties, even when the material of the housing main body 3is unknown, or even when the internal structure of the housing main body3 that cannot be seen from the outside is unknown, optimum cuttingconditions can be set automatically, thus achieving the automation ofthe cutting work.

In the above description, the cutting device 10 can be replaced with thecutting device 100 illustrated in Embodiment B-2. In this case, theabove-mentioned control device can be provided for each rotating unit.In other words, the control device detects at least one of an intrinsicoscillatory waveform and an intrinsic oscillation frequency that arecaused by the impact of the impacting bodies against the housing mainbody 3, the load on the driving motor for rotating each rotating unitand an outer shape of the workpiece and change at least one of therotational speed, a cutting depth and a relative speed and a relativemoving direction between the rotating unit and the housing main body 3for each of the rotating units. In this manner, it is possible to set anappropriate cutting condition for each rotating unit.

Furthermore, instead of mounting the cutting device 100 of EmbodimentB-2 including the first and second rotating units to one robot, it alsois possible to provide a plurality of robots, each of which is providedwith one rotating unit, and increase the cutting depth sequentially,thereby cutting into the housing main body 3 sequentially, for example.

It is needless to say that the conveyor system may be a belt conveyor ora chain conveyor.

C. Compressing Process

After being cut into a predetermined size and shape in the cutting andseparating process described above, resultant pieces are sent to thecompressing process. In the compressing process, the heat insulator iscompressed so as to collect a gas (a foaming gas, for example,chlorofluorocarbons) contained therein.

FIG. 24 shows a schematic configuration of a compressing device 300 usedin the compressing process.

The compressing device 300 has four pairs of compression rollers forcompressing, from above and below, a piece to be compressed 350 obtainedby cutting the heat-insulating housing. They are first preliminarycompression rollers 311 a, 311 b, second preliminary compression rollers312 a, 312 b, third preliminary compression rollers 313 a, 313 b andmain compression rollers 320 a, 320 b. These four pairs of compressionrollers are arranged such that the rollers in each pair oppose eachother substantially in parallel and have a space therebetween, the spacegradually decreasing in this order. Each space between the pair ofrollers can be adjusted according to the piece to be compressed 350. Thecompression rollers are rotated and driven in directions indicated byarrows in FIG. 24. A rotational shaft of the upper main compressionroller 320 a is held by a piston 322, and a pressurizing mechanism 325constituted by the piston 322 and a hydraulic cylinder 324 applies apredetermined compressive force between the main compression rollers 320a, 320 b. A shaft of the piston 322 is provided with a pressuredetection device (for example, a load cell) 327 for detecting acompressive force, with which the compressive force between the maincompression rollers 320 a, 320 b is detected, and then a compressiveforce applied by the pressurizing mechanism 325 is adjusted.

A compressing chamber 310 containing the above-described four pairs ofcompression rollers is covered with an upper cover 330 a and a lowercover 330 b. The upper cover 330 a is provided with suction ducts 332 a,332 b, whose ends are connected to a suction pump (not shown in thefigure).

The piece to be compressed 350 is sent into the compressing device 300by a carrier device 340 and, after being compressed, sent out by acarrier device 345. The carrier device 340 is a belt conveyorconstituted by a pair of rollers 341, 342 rotating in the arrowdirections and an endless belt 344 running between them. Similarly, thecarrier device 345 is a belt conveyor constituted by a pair of rollers346, 347 rotating in the arrow directions and an endless belt 349running between them. The upper surfaces of the carrier devices 340, 345are designed to be at substantially the same height as the upperportions of the peripheral surfaces of the compression rollers 311 b,312 b, 313 b and 320 b.

The following is a description of an operation of the compressing deviceconfigured as above.

After being cut in a suitable size and shape, the piece to be compressed350 of the heat-insulating housing is sent to the compressing device 300by the carrier device 340. The piece to be compressed 350 is a layeredbody formed of a steel plate layer 351, a heat insulator layer (aurethane foam layer) 352 and a resin plate layer 353. The heat insulatorlayer 352 of the piece 350 is compressed sequentially by the four pairsof compression rollers within the compressing device 300 and then almostcompletely squashed, especially by the last main compression rollers 320a, 320 b, to such an extent that the steel plate layer 351 and the resinplate layer 353 nearly contact each other. By carrying out thecompression using the rollers, a heavy load can be applied to a minutearea. Furthermore, since a micro shearing force caused by the rollerrotation can be generated in the heat insulator layer 352, all theclosed-cells in the heat insulator layer 352 can be crushed easily andreliably, thereby squeezing a contained gas therefrom. In order toprevent the slip between the compression rollers and the piece 350,generate the above-mentioned shearing force reliably and improve theabove-mentioned squeezing effect, roughness similar to that formed forknurling (for example, meshed grooves, longitudinal grooves, obliquegrooves, dotted protrusions or recesses) may be formed on a peripheralsurface of each of the compression rollers (in particular, the maincompression rollers 320 a, 320 b). The compressive force of the maincompression roller 320 a during compression is monitored constantly bythe pressure detection device 327. When the compressive force risesabnormally for such a reason that uncompressible foreign substances aremixed in the piece 350, the operation of adjusting the pressurizingmechanism 325 so as to reduce the compressive force or that of makingall the compression rollers repeat rotating forward and backward isperformed automatically.

During the compression, many closed-cells present inside the heatinsulator layer 325 are crushed, so that a gas contained in those cells(for example, chlorofluorocarbons) is released. The gas is confinedwithin the compressing chamber 310 constituted by the upper cover 330 aand the lower cover 330 b and not diffused outside. Generally, becauseits specific gravity is smaller than the air, this gas gathers upwardand then is collected through the suction ducts 332 a, 332 b. Thecompressed piece 350 is carried out by the carrier device 345.

The piece 350 that has been carried out can be directly put into a blastfurnace to make iron and then used again, for example. At this time, thelaminated heat insulator layer 352 and resin plate layer 353 can beburnt in the blast furnace and used as a heat source. Since the foaminggas (chlorofluorocarbons) already is collected, there is no concernabout the generation of a toxic gas such as a chlorine gas.

As described above, in accordance with the compressing device of thepresent invention, the foaming gas can be collected at a highconcentration without being diffused in the air. Thus, it becomes easierto concentrate and separate the foaming gas, and simple equipment issufficient for such operations, making it possible to achieve theminiaturization of equipment and the const reduction.

In order to lead out the foaming gas contained in the heat insulator, itis appropriate just to cut the heat-insulating housing of therefrigerator into a suitable-sized pieces with the steel plate and theresin plate being attached and to put them into the compressing deviceof the present invention. In other words, conventional processes ofremoving the steel plate and the resin plate from the heat insulator,crushing the heat insulator into fine pieces and separating the crushedmaterial and the gaseous component all become unnecessary. Accordingly,the processes are simplified, so that the equipment becomes simpler andsmaller and costs less.

Moreover, the compressed pieces can be put into a blast furnace directlyand then used again.

Consequently, in accordance with the present invention, it is possibleto achieve a disassembling of an unwanted refrigerator and a recyclingsystem thereof easily at low cost.

Although FIG. 24 illustrates the configuration in which the compressingchamber 310 is covered with the upper and lower covers 330 a, 330 b, thepresent invention is not limited to the above configuration. Forexample, an openable door may be provided in each of an entrance throughwhich the piece to be compressed 350 is put in and an exit through whichthe compressed piece is carried out, so that the compressing chamber 310is completely sealed by the covers 330 a, 330 b and these doors duringcompression.

The arrangement of the compression rollers is not limited to theconfiguration of FIG. 24 as long as at least one pair of compressionrollers that are arranged to oppose each other can compress the piece.For example, on the other side of the piece to be compressed withrespect to the compression roller for contacting directly andcompressing the piece to be compressed, a back-up roll may be providedfor preventing a deflection of the compression roller. A so called crownroll, whose central diameter is larger than the diameter on both ends inits width direction also may be used for achieving a compressive forcethat is uniform along the width direction. Furthermore, the pair ofcompression rollers opposing each other may have a different outershape.

In addition, the carrier devices 340 and 345 do not have to be the beltconveyor as shown in FIG. 24, but can be a roller conveyor, for example,or other known carrier mechanisms.

Furthermore, the cutting device and the compressing device can beconnected by the carrier device, so that the pieces that have been cutand separated in the cutting device are carried to the compressingdevice automatically or semi-automatically. For example, both thedevices can be connected by a belt conveyor or a roller conveyor, or thecut pieces can be transferred onto the carrier device 340 of thecompressing device using a robot arm. This can improve a work efficiencyof disassembling a refrigerator.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The embodimentsdisclosed in this application are to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, all changes that come within the meaning and range ofequivalency of the claims are intended to be embraced therein.

INDUSTRIAL APPLICABILITY

In accordance with the present invention, it is possible to disassemblea refrigerator while collecting a foaming gas efficiently at low costusing a small device. Therefore, the present invention can be usedsuitably for a recycling system of a discarded refrigerator.

1. A compressing device comprising: at least a pair of compressionrollers opposing each other for compressing/processing an object to becompressed; a gas diffusion preventing device for preventing a diffusionof a gas leaking from the object to be compressed during compressing;and a gas collecting device for collecting the gas.
 2. The compressingdevice according to claim 1, further comprising a carrier device forcarrying the object to be compressed.
 3. The compressing deviceaccording to claim 2, wherein the carrier device is a belt conveyor. 4.The compressing device according to claim 1, wherein the object to becompressed is a piece obtained by cutting a heat-insulating housing of arefrigerator.